Biomechanical and clinical study of single posterior oblique cage POLIF in the treatment of degenerative diseases of the lumbar spine

Introduction

Aim of the study was to evaluate the biomechanical stability and the clinical efficacy of a lumbar interbody fusion obtained by single oblique cage implanted by a posterior approach.

Method

Through the realization of three finite element models (FEMs), the biomechanics of POLIF was compared to PLIF and TLIF. Ninety-four patients underwent interbody fusion by POLIF with instrumented posterolateral fusion. Clinical and radiographic outcomes were evaluated at regular intervals for at least 6 months.

Results

The FEMs showed no statistically significant differences in stability in compression and flexion–extension. Mean preoperative VAS score was 7.1, decreased to 2.1 at follow-up. Mean preoperative SF-12 value was 34.5 %, increased to 75.4 % at follow-up. All patients showed a good fusion rate and no hardware failure.

Discussion

POLIF associated to instrumented posterolateral fusion is a viable and safe surgical technique, which ensures a biomechanical stability similar to other surgical techniques.

     

Comparative study of serum pancreatic isoamylase, lipase, and trypsin-like immunoreactivity in pancreatic disease

Serum total amylase, pancreatic and salivary isoamylase, lipase and trypsin-like immunoreactivity (TLI) were measured in 16 patients with acute pancreatitis, 37 patients with chronic pancreatitis, 11 patients with pancreatic cancer, and 53 control subjects in order to evaluate the relative value of these tests in the diagnosis of pancreatic disease. In acute pancreatitis patients studied within 2 days from the onset of pain all pancreatic enzymes were abnormally high. In chronic pancreatitis patients serum pancreatic isoamylase and TLI were abnormally low in 8 out of 10 patients with severely impaired pancreatic exocrine function, while lipase was abnormally low in 6 patients. During acute exacerbations of the disease elevated levels of pancreatic isoamylase and lipase, but not of TLI, were found in about one third of cases. In patients with pancreatic cancer the pattern of changes in serum pancreatic enzymes was variable since levels within, below and above the normal range were found. The results demonstrate that in acute pancreatitis all serum pancreatic enzymes had the same diagnostic sensitivity, however serum lipase determination is the most convenient because of its simplicity and low cost. In chronic pancreatitis serum pancreatic isoamylase and TLI may be useful in detecting severe pancreatic insufficiency. In pancreatic cancer serum pancreatic enzymes lack diagnostic specificity.     

Serum amylase and lipase concentrations and lipase/amylase ratio in assessment of etiology and severity of acute pancreatitis

We studied the behavior of serum amylase and lipase in 66 consecutive patients with acute pancreatitis in order to assess the ability of these tests and of the serum lipase-amylase ratio to establish the etiology and predict the severity of acute pancreatitis. Forty-two patients had biliary acute pancreatitis, 14 had alcoholic acute pancreatitis, and the remaining 10 nonbiliary, nonalcoholic (NBNA) acute pancreatitis. Serum amylase and lipase were abnormally high in all patients. The elevations of both serum amylase and lipase were significantly lower in patients with alcoholic pancreatitis than in those with biliary pancreatitis, although a considerable overlap was observed between the two groups. No statistically significant differences were found between NBNA patients and those with either biliary or alcoholic forms of the disease. The serum lipase-amylase ratios in patients with alcoholic pancreatitis ranged from 0.2 to 5.6, in those with biliary pancreatitis from 0.1 to 7.9, and in those with NBNA pancreatitis from 0.1 to 4.4. These differences were not statistically significant. No differences in serum enzyme levels were observed among patients without apparent imaging signs of acute pancreatitis (N=20), those with signs of Pancreatic edema (N=36), and those with necrotizing pancreatitis (N=10). The results indicate that serum amylase and lipase concentrations are not able to establish either the etiology or to predict the severity of acute pancreatitis as assessed by imaging techniques. Furthermore, the serum lipase-amylase ratio is not useful in distinguishing acute episodes of alcoholic from nonalcoholic acute pancreatitis.     

Cold denaturation and 2H2O stabilization of a staphylococcal nuclease mutant.

Cold denaturation is now recognized as a general property of proteins but has been observed only under destabilizing conditions, such as moderate denaturant concentration or low pH. By destabilizing the protein using site-directed mutagenesis, we have observed cold denaturation at pH 7.0 in the absence of denaturants in a mutant of staphylococcal nuclease, which we call NCA S28G for a hybrid protein between staphylococcal nuclease and concanavalin A in which there is the point mutation Ser-28----Gly. The temperature of maximum stability (tmax) as determined by circular dichroism (CD) was 18.1 degrees C, and the midpoints of the thermal unfolding transitions (tm) were 0.6 degrees C and 30.0 degrees C. These values may be compared with the tm of 52.5 degrees C for wild-type staphylococcal nuclease, for which no cold denaturation was observed under these conditions. When the stability of the mutant was examined in 2H2O by NMR, CD, or fluorescence, a substantial increase in the amount of folded protein at the tmax was noted as well as a decrease in tmax, reflecting increased stability.     

Ebola viral load at diagnosis associates with patient outcome and outbreak evolution

BACKGROUND. Ebola virus (EBOV) causes periodic outbreaks of life-threatening EBOV disease in Africa. Historically, these outbreaks have been relatively small and geographically contained; however, the magnitude of the EBOV outbreak that began in 2014 in West Africa has been unprecedented. The aim of this study was to describe the viral kinetics of EBOV during this outbreak and identify factors that contribute to outbreak progression.METHODS. From July to December 2014, one laboratory in Sierra Leone processed over 2,700 patient samples for EBOV detection by quantitative PCR (qPCR). Viremia was measured following patient admission. Age, sex, and approximate time of symptom onset were also recorded for each patient. The data was analyzed using various mathematical models to find trends of potential interest.RESULTS. The analysis revealed a significant difference (P = 2.7 × 10^–77) between the initial viremia of survivors (4.02 log₁₀ genome equivalents [GEQ]/ml) and nonsurvivors (6.18 log₁₀ GEQ/ml). At the population level, patient viral loads were higher on average in July than in November, even when accounting for outcome and time since onset of symptoms. This decrease in viral loads temporally correlated with an increase in circulating EBOV-specific IgG antibodies among individuals who were suspected of being infected but shown to be negative for the virus by PCR.CONCLUSIONS. Our results indicate that initial viremia is associated with outcome of the individual and outbreak duration; therefore, care must be taken in planning clinical trials and interventions. Additional research in virus adaptation and the impacts of host factors on EBOV transmission and pathogenesis is needed.     

Tumor M2-Pyruvate Kinase, a New Metabolic Marker for Pancreatic Cancer

An isoenzyme of pyruvate kinase (Tu M2-PK) is overexpressed by tumor cells and can be measured in blood by a specific immunoenzymatic assay. Our objective was to investigate the diagnostic value of Tu M2-PK in comparison with that of CA 19-9 in pancreatic cancer. We studied 265 subjects: 60 with histologically confirmed pancreatic cancer, 43 with benign pancreatic diseases (acute and chronic pancreatitis), 5 with benign cystic neoplasms of the pancreas, 9 with neuroendocrine tumors, 77 with other abdominal malignancies, 47 with benign digestive diseases, and 24 healthy controls. Levels of plasma Tu M2-PK and serum CA 19-9 were determined by commercially available specific immunoassays. The diagnostic sensitivity and specificity of Tu M2-PK for pancreatic cancer were 85 and 41%, respectively, while those of CA 19-9 were 75 and 81%. The combination of the two tests significantly increased sensitivity (97%) but lowered specificity (38%). In discriminating between pancreatic cancer and acute or chronic pancreatitis, Tu M2-PK turned out to be less accurate than CA 19-9. In patients without pancreatic tumor, cholestasis appeared not to affect the values of Tu M2-PK, while CA 19-9 was found to be significantly higher. Tu M2-PK was also abnormally high in the majority of patients with other digestive malignancies or neuroendocrine tumors. The results demonstrate that Tu M2-PK has a satisfactory sensitivity but a poor specificity in the diagnosis of pancreatic cancer. Used together with CA 19-9, the sensitivity increases considerably.     

HLA-B13 and chronic calcific pancreatitis

In view of a possible role of genetic factors in the etiology of chronic calcific pancreatitis, we undertook a study of the frequency of HLA antigens in this disease. Sixty-four patients with chronic calcific pancreatitis were typed for the HLA-A,-B and-C loci. Fourteen of these 64 patients (21.9%) were found to have antigen B13 compared to 7.5% of 425 controls. These results have aP value of 0.00059 which remains significant (P=0.020) even when multiplied by the total number of antigens tested. Sex, alcoholism, age at the clinical onset of the disease, presence of pain, and diabetes had no apparent influence on the distribution of HLA alleles. The significant association between chronic calcific pancreatitis and HLA antigen B13 further supports the role of genetic factors in the etiology of the disease.     

Evaluation of Pyrosequencing for Detecting Extensively Drug-Resistant Mycobacterium tuberculosis among Clinical Isolates from Four High-Burden Countries

Reliable molecular diagnostics, which detect specific mutations associated with drug resistance, are promising technologies for the rapid identification and monitoring of drug resistance in Mycobacterium tuberculosis isolates. Pyrosequencing (PSQ) has the ability to detect mutations associated with first- and second-line anti-tuberculosis (TB) drugs, with the additional advantage of being rapidly adaptable for the identification of new mutations. The aim of this project was to evaluate the performance of PSQ in predicting phenotypic drug resistance in multidrug- and extensively drug-resistant tuberculosis (M/XDR-TB) clinical isolates from India, South Africa, Moldova, and the Philippines. A total of 187 archived isolates were run through a PSQ assay in order to identify M. tuberculosis (via the IS6110 marker), and to detect mutations associated with M/XDR-TB within small stretches of nucleotides in selected loci. The molecular targets included katG, the inhA promoter and the ahpC-oxyR intergenic region for isoniazid (INH) resistance; the rpoB core region for rifampin (RIF) resistance; gyrA for fluoroquinolone (FQ) resistance; and rrs for amikacin (AMK), capreomycin (CAP), and kanamycin (KAN) resistance. PSQ data were compared to phenotypic mycobacterial growth indicator tube (MGIT) 960 drug susceptibility testing results for performance analysis. The PSQ assay illustrated good sensitivity for the detection of resistance to INH (94%), RIF (96%), FQ (93%), AMK (84%), CAP (88%), and KAN (68%). The specificities of the assay were 96% for INH, 100% for RIF, FQ, AMK, and KAN, and 97% for CAP. PSQ is a highly efficient diagnostic tool that reveals specific nucleotide changes associated with resistance to the first- and second-line anti-TB drug medications. This methodology has the potential to be linked to mutation-specific clinical interpretation algorithms for rapid treatment decisions.